It sounds like your program is listening on a socket. Normally, when your program exits the OS closes all sockets that might be open (including listening sockets). However, for listening sockets the OS normally reserves the port for some time (several minutes) after your program exits so it can handle any outstanding connection attempts. You … Read more
This is a known JVM bug in C2 compiler: JDK-8154831. Try adding the following JVM argument: -XX:CompileCommand=exclude,org.eclipse.jdt.internal.compiler.parser.TypeConverter::*
Java Objects can be created in several different ways. From Java code, when a Java method, either interpreted or compiled, executes one of the following bytecode instructions: new, newarray, anewarray, multianewarray. From native code, when native methods, including those in standard class library, call one of JNI functions: NewObject, NewObjectArray, NewStringUTF, NewDirectByteBuffer, etc. Directly from … Read more
From: http://www.oracle.com/technetwork/java/hotspotfaq-138619.html#64bit_performance “Generally, the benefits of being able to address larger amounts of memory come with a small performance loss in 64-bit VMs versus running the same application on a 32-bit VM. This is due to the fact that every native pointer in the system takes up 8 bytes instead of 4. The loading of … Read more
After compilation some strings may refer to the one instance, so, you will edit more than you want and never know what else are you editing. public static void main(String args[]) throws Exception { String s1 = “Hello”; // I want to edit it String s2 = “Hello”; // It may be anywhere and must … Read more
I guess that when GC (Garbage Collector) is working the application stops and resumes when GC finishes I don’t think that is a safe assumption. Are you sure the garbage collector is not working in parallel with your application code? To measure the time spent in collecting garbage you can query the Garbage Collector MXBean. … Read more
I discovered yesterday that there is a problem with Java versions on Windows, as you know keeping java up to date these days is critical, especially the JRE used by Internet explorer located in the Windows system32 or syswow64 folder. You can perform a search for java in your C: drive and look at the … Read more
On Linux I’m using the resource module: import resource resource.setrlimit(resource.RLIMIT_AS, (megs * 1048576L, -1L))
Update (March 2012): Oracle appears to have quietly disassembled their JavaRTS development team. There isn’t a good answer to this question. There certainly isn’t enough critical mass to say there’s a current most-popular RT JVM. US Defense systems I’m aware of use JavaRTS, IBM’s WebSphere RT, and PERC. Aviation platforms use aicas JamaicaVM. Most of … Read more
The Java Virtual Machine takes two command line arguments which set the initial and maximum heap sizes: -Xms and -Xmx. You can add a system environment variable named _JAVA_OPTIONS, and set the heap size values there. For example if you want a 512Mb initial and 1024Mb maximum heap size you could use: under Windows: SET … Read more